Subcutaneous Administration is Preferred for Filgrastim in HSC Mobilization
Subcutaneous (SC) administration is the preferred and standard route for filgrastim in hematopoietic stem cell mobilization, with intravenous (IV) administration being technically possible but not recommended by major guidelines. 1, 2
Guideline Recommendations on Route of Administration
The evidence strongly favors subcutaneous administration:
The National Comprehensive Cancer Network explicitly states that the subcutaneous route is preferred for all myeloid growth factors including filgrastim, with IV administration being technically possible but not the standard approach. 1, 2
The American Society of Clinical Oncology emphasizes subcutaneous injection as the standard approach for filgrastim administration, with strength of evidence based on multiple clinical trials. 2
For HSC mobilization specifically, the standard regimen is filgrastim 10 mcg/kg/day subcutaneously starting 4 days before the first leukapheresis procedure and continuing through the last leukapheresis. 3
Clinical Trial Evidence
The FDA label provides important context from transplant studies:
In bone marrow transplant studies (Studies 6 and 9), filgrastim was administered both as 24-hour continuous IV infusion and as continuous subcutaneous infusion, with both routes showing efficacy in reducing duration of severe neutropenia. 4
However, for peripheral blood progenitor cell mobilization and collection (Study 11), filgrastim was administered subcutaneously by injection or continuous IV infusion, with the subcutaneous route being the predominant method used. 4
Multiple research studies in lymphoma patients specifically used subcutaneous administration for HSC mobilization with excellent results, achieving target CD34+ cell collection goals. 5, 6
Practical Considerations
There is no evidence demonstrating superior efficacy of IV over SC administration for HSC mobilization, and SC administration offers practical advantages:
SC administration allows for outpatient self-administration or home nursing, reducing healthcare resource utilization. 2
Site rotation is recommended when administering multiple doses over several days to prevent local tissue irritation. 2
The subcutaneous route provides sustained drug exposure appropriate for the mobilization process, which typically requires 4-7 days of daily dosing. 3, 4
Critical Caveat for Your Hodgkin Lymphoma Patient
For a patient with relapsed Hodgkin lymphoma undergoing HSC mobilization:
Use subcutaneous filgrastim 10 mcg/kg/day starting 4 days before first leukapheresis. 3, 4
If the patient has been heavily pretreated, SC administration remains the standard despite potentially requiring more leukapheresis sessions to reach target cell collection. 6
The IV route should only be considered if there are specific contraindications to SC administration (such as severe subcutaneous tissue abnormalities or coagulopathy), but this is not a standard practice and lacks guideline support. 1, 2